There's a lot of activity around the Czech Jabber community right now and many users are starting to think about their own Jabber (XMPP) server. XMPP is an open protocol, so there's no reason why anyone couldn't do it. But there are so many Linux implementations and you probably don't know which one to choose. Do you have fifteen minutes to spare? If you don't know anything about XMPP servers and you've just decided to try one, you'll probably be very confused at the beginning and the best alternatives will end up being hidden from you anyway. More here.